Abstract

A group of magnesia-graphite and magnesia-graphite-aluminum materials, the compositions of which represent a wide range of graphite contents (approximately 10-16.4 wt.%), aluminum contents (0-5.2 wt.%), and MgO and graphite qualities, were fabricated, using standard commercial practices. Chemical analysis and determination of room-temperature modulus of rupture (MOR) and Young's modulus, as well as a complete microstructural characterization of the as-received materials, were performed. Mechanical characterization at high temperature (1000°, 1200°, and 1450 °C) was done in terms of Young's modulus and MOR in an argon atmosphere (°C). Modulus-of-elasticity values ranged from 4 to 16 GPa, and their evolution with temperature was determined by the evolution of the microstructure in the bulk of the specimens. A strong effect of aluminum-metal concentration on Young's modulus overrode other microstructural differences among the materials. MOR values ranged from 6 to 20 MPa, and their evolution with temperature was determined by the evolution of the microstructure in the bulk of the specimens at the lower testing temperatures (T ≤ 1200 °C) and by phase assemblages in the surface regions of the specimens - essentially by the presence of the dense MgO zone - at 1450 °C. The thickness of the dense MgO zone in the aluminum-containing materials was determined by the amount of aluminum and the MgO aggregate size.

Department(s)

Materials Science and Engineering

Publication Status

Full Access

International Standard Serial Number (ISSN)

0002-7820

Document Type

Article - Journal

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Citation

File Type

text

Language(s)

English

Rights

© 2024 Wiley, All rights reserved.

Publication Date

01 Jan 1999

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